I just install my keys as needed to the machines and then configure aliases for quick connections. For file transfer with SFTP I’m using Filezilla because its queuing functionality and site management are nice.
I think for what you are looking for, both puTTY and Remmina should be capable as well as the other options suggested here
I like how their whole excuse to that was “WE DIDN’T SEED ANY OF IT BACK THOUGH” which arguably makes it even worse lol.